Mental Timeline Research Articles

With the past behind and the future ahead: Back-to-front representation of past and future sentences

Several studies support the psychological reality of a mental timeline that runs from the left to the right and may strongly affect our thinking about time. Ulrich and Maienborn (Cognition 117:126-138, 2010) examined the linguistic relevance of this timeline during the processing of past- and future-related sentences. Their results indicate that the timeline is not activated automatically during sentence comprehension. While no explicit reference of temporal expressions to the left-right axis has been attested (e.g., *the meeting was moved to the left), natural languages refer to the back-front axis in order to encode temporal information (e.g., the meeting was moved forward). Therefore, the present study examines whether a back-frontal timeline becomes automatically activated during the processing of past- and future-related sentences. The results demonstrate a clear effect on reaction time that emerges from a time-space association along the frontal timeline (Experiment 1). However, this activation seems to be nonautomatic (Experiment 2), rendering it unlikely that this frontal timeline is involved in comprehension of the temporal content of sentences.

Prismatic adaptation effects on spatial representation of time in neglect patients

Processing of temporal information may require the use of spatial attention to represent time along a mental time line. We used prismatic adaptation (PA) to explore the contribution of spatial attention to the spatial representation of time in right brain damaged patients with and without neglect of left space and in age-matched healthy controls.Right brain damaged patients presented time underestimation deficits, that were significantly greater in patients with neglect than in patients without neglect. PA inducing leftward attentional deviation reduced time underestimation deficit in patients with neglect.The results support the hypothesis that a right hemispheric network has a role, per se, in time perception. Moreover, they suggest that right hemisphere is important in time perception for its control of spatial attention, engaged in spatial representation of time. Procedures that ameliorate left spatial deficits could also be useful for modulating temporal deficits in right brain damaged patients with neglect.

Is the Future the Right Time?

Spanish and English speakers tend to conceptualize time as running from left to right along a mental line. Previous research suggests that this representational strategy arises from the participants' exposure to a left-to-right writing system. However, direct evidence supporting this assertion suffers from several limitations and relies only on the visual modality. This study subjected to a direct test the reading hypothesis using an auditory task. Participants from two groups (Spanish and Hebrew) differing in the directionality of their orthographic system had to discriminate temporal reference (past or future) of verbs and adverbs (referring to either past or future) auditorily presented to either the left or right ear by pressing a left or a right key. Spanish participants were faster responding to past words with the left hand and to future words with the right hand, whereas Hebrew participants showed the opposite pattern. Our results demonstrate that the left-right mapping of time is not restricted to the visual modality and that the direction of reading accounts for the preferred directionality of the mental time line. These results are discussed in the context of a possible mechanism underlying the effects of reading direction on highly abstract conceptual representations.

Left–right coding of past and future in language: The mental timeline during sentence processing

The metaphoric mapping theory suggests that abstract concepts, like time, are represented in terms of concrete dimensions such as space. This theory receives support from several lines of research ranging from psychophysics to linguistics and cultural studies; especially strong support comes from recent response time studies. These studies have reported congruency effects between the dimensions of time and space indicating that time evokes spatial representations that may facilitate or impede responses to words with a temporal connotation. The present paper reports the results of three linguistic experiments that examined this congruency effect when participants processed past- and future-related sentences. Response time was shorter when past-related sentences required a left-hand response and future-related sentences a right-hand response than when this mapping of time onto response hand was reversed (Experiment 1). This result suggests that participants can form time–space associations during the processing of sentences and thus this result is consistent with the view that time is mentally represented from left to right. The activation of these time–space associations, however, appears to be non-automatic as shown by the results of Experiments 2 and 3 when participants were asked to perform a non-temporal meaning discrimination task.

The right time and the left time: Spatial associations of temporal cues affect target detection in right brain-damaged patients

Humans map timewords such as “yesterday” or “future” onto a mental timeline that holds temporally earlier events on the left side of space and temporally later events on the right side. The perception of time and spatial mapping both are partially subserved by right temporo-parietal brain regions. We tested stroke patients with right-hemisphere lesions on a spatio-temporal cueing task to see whether spatial associations of noninformative temporal cues would elicit the same cognitive deficits as do typical stimulus-driven exogenous cues. While our right brain-damaged patients were able to maintain a mental timeline with words referring to the past sitting to the left and words referring to the future sitting to the right, we also observed that the typical deficit in disengaging from incongruently cued locations persists for noninformative cues that are mapped onto a mental spatial continuum.

Thinking about the future moves attention to the right.

Previous studies have shown that past and future temporal concepts are spatially represented (past being located to the left and future to the right in a mental time line). This study aims at further investigating the nature of this space-time conceptual metaphor, by testing whether the temporal reference of words orient spatial attention or rather prime a congruent left/right response. A modified version of the spatial cuing paradigm was used in which a word's temporal reference must be kept in working memory whilst participants carry out a spatial localization (Experiment 1) or a direction discrimination, spatial Stroop task (Experiment 2). The results showed that the mere activation of the past or future concepts both oriented attention and primed motor responses to left or right space, respectively, and these effects were independent. Moreover, in spite of the fact that such time-reference cues were nonpredictive, the use of a short and a long stimulus onset asynchrony in Experiment 3 showed that these cues modulated spatial attention as typical central cues like arrows do, suggesting a common mechanism for these two types of cuing.

The mental time line: An analogue of the mental number line in the mapping of life events

A crucial aspect of the human mind is the ability to project the self along the time line to past and future. It has been argued that such self-projection is essential to re-experience past experiences and predict future events. In-depth analysis of a novel paradigm investigating mental time shows that the speed of this “self-projection” in time depends logarithmically on the temporal-distance between an imagined “location” on the time line that participants were asked to imagine and the location of another imagined event from the time line. This logarithmic pattern suggests that events in human cognition are spatially mapped along an imagery mental time line. We argue that the present time-line data are comparable to the spatial mapping of numbers along the mental number line and that such spatial maps are a fundamental basis for cognition.

Spatial–temporal interactions in the human brain

The review summarises current evidence on the cognitive mechanisms for the integration of spatial and temporal representations and of common brain structures to process the where and when of stimuli. Psychophysical experiments document the presence of spatially localised distortions of sub-second time intervals and suggest that visual events are timed by neural mechanisms that are spatially selective. On the other hand, experiments with supra-second intervals suggest that time could be represented on a mental time-line ordered from left-to-right, similar to what is reported for other ordered quantities, such as numbers. Neuroimaging and neuropsychological findings point towards the posterior parietal cortex as the main site where spatial and temporal information converge and interact with each other.

Time flies like an arrow: Space-time compatibility effects suggest the use of a mental timeline

The concept of time is elusive to direct observation, yet it pervades almost every aspect of our daily lives. How is time represented, given that it cannot be perceived directly? Metaphoric mapping theory assumes that abstract concepts such as time are represented in terms of concrete, readily available dimensions. Consistent with this, many languages employ spatial metaphors to describe temporal relations. Here we investigate whether the time-is-space metaphor also affects visuospatial attention. In a first experiment, subjects categorized the names of actors in a manner compatible or incompatible with the orientation of a timeline. In two further experiments, subjects categorized or detected left- or right-side targets following prospective or retrospective time words. All three experiments show compatibility effects between the dimensions of space (left-right) and time (earlier-later) and indicate that the concept of time does indeed evoke spatial associations that facilitate responses to targets at spatially compatible locations.

Horizontal spatial representations of time: Evidence for the STEARC effect

It is well known that stimuli such as numerals (small vs large) and auditory pitches (low vs high) have spatial characteristics, and that responses to such stimuli are biased by the mental representation of their magnitude. Walsh (2003) has argued that any spatially and action-coded magnitude will yield a relationship between magnitude and space. Here we investigated the spatial representation of ‘time’ using speeded responses to the onset timing (early vs late) of a probe stimulus following periodic auditory clicks. Participants pressed one of the two response keys depending on whether the timing of a given probe was earlier or later than expected based on the preceding clicks. The results showed that left-side responses to early onset timing were faster than those to late onset timing, whereas right-side responses to late onsets were faster than those to early onsets when the response keys were aligned horizontally. Such a time–response congruity effect was not observed with the vertical alignment of responses. These results suggest that time is represented from left to right along the horizontal axis in space. The existence of a ‘ mental time line’ in space and the spatial–temporal association of response codes (STEARC) effect are discussed.